An ultra-high frequency radio communication system using mmWave is configured to operate at a center frequency in the range of several GHz to several tens of GHz. Due to such a center frequency feature, significant path loss may occur in a shadow area in the mmWave communication system. Considering that a synchronization signal should be stably transmitted to all user equipments (UEs) located within coverage of a base station (BS), the synchronization signal needs to be designed and transmitted in consideration of the potential deep-null phenomenon, which may occur due to the above-described ultra-high frequency band characteristic, in the mmWave communication system.